The present invention relates to pressure regulating valve.
Pressure regulating valves operate in a fuel injection system of internal combustion engines with fuel pumps preferably arranged in a fuel tank for regulation of a system pressure.
A known pressure regulating valve of this type in a fuel supply system for internal combustion engine is disclosed in the German patent document DE 42 31 731 A1. In this pressure regulating valve, the valve closing spring is supported between the valve member and an adjusting screw which is screwed at the end side in the control chamber, so that the spring force of the valve closing spring and thereby the fuel pressure regulated by the pressure regulating valve in a discharge can be adjusted. When the fuel pressure applied in the valve chamber of the fuel pump reaches an opening pressure provided by the spring force F of the valve closing spring and the cross-section A of the valve opening, the valve member is lifted from the valve seat and controls so much overflow quantity Q that the regulating pressure p.sub.r =F/A is adjusted. The regulating pressure p.sub.r depends from the throughflow quantity Q, since with increasing through flow quantity Q the stroke of the valve member is increased and thereby the spring force F is increased due to the spring strength of the valve closing spring. The characteristic line p.sub.r (Q) of the pressure regulating valve which exhibits the operational dependency of the regulating pressure p.sub.r from the discharge quantity, has thereby an increase. In other words, the regulating pressure increases with the throughflow quantity.